Camera equipment typically does not require more that the skill of its operator to keep the camera aimed at its subject. However when the operator is also the subject, he has no way of knowing whether the camera is properly aimed. Developers of early video telephone systems, such as AT&T's Picturephone service, realized that this was a major problem needing solution because the whole purpose behind Picturephone service was to allow each party to see the other during a telephone conversation. The Picturephone product comprised a video camera mounted above a miniature display screen (television) in a single housing. Each party to this service could see the other on the screen while being the subject of the video camera. During the conversation, the parties would need to tell each other that they needed to move a little to the left or right so that they could be seen.
One solution that has been proposed is the use of a light emitting indication member which can be observed from any position within the range of the scene to be photographed. This solution is discussed in U.S. Pat. No. 4,490,029 in connection with camera photography when the photographer wants to become part of the picture. Continual reminders of the presence of the equipment is a distraction that calls too much attention to the limitations of the equipment. Human factors considerations in the design of such equipment suggests that it should be transparent to the parties and obvious to use. With this in mind, the facts remain that the camera is stationary, and human subjects are prone to move.
A solution that was used in Picturephone service was a "self view" feature wherein the subject would depress a button to see, on the display screen, how he looked to the distant party. In particular, he could determine whether he was in the center of the picture or off to one side. While this particular technique is generally useful, it requires the subject to be actively concerned with the operation of the equipment which, as discussed above, is undesirable.
Another solution is to use a "split screen" in which a portion of the screen is devoted to self view where the subject continually observes his appearance, Apart from narcissism, encouraged by this practice, it is a distraction that diverts the subject's attention from the message toward the media, and takes up too much space on the already small display screen.
Still another solution is to arrange for the camera to automatically track its subject. This would allow the subject to move around naturally to different positions without ever worrying whether he will be seen by the distant party. An example of such a system is disclosed in U.S. Pat. No. 3,419,674 which was issued to R. V. Burns et al. on Dec. 31, 1968. Burns teaches an apparatus for automatically positioning a movably mounted television camera in response to the movement of a subject. Video signals, indicating transitions between the subject and the background, are used together with horizontal and vertical sync pulses to generate a control signal for a motor that moves the television camera. Unfortunately, automatic tracking is costly to implement and may not be needed in most applications.